So after boosting my Is the left engine mount got weak and started to crack. Before any serious damage happened I ordered new Megan replacement mounts and figured I would take some pics along to help guide others planning on replacing engine mounts in the IS300.
Please use this guide at your own risk and only proceed if you are technically inclined and capable, I am not responsible for your actions or mistakes and if you damage your vehicle. A shop lift is the easiest way to this procedure. You will need a trans jack and adjustable support jack also.
Start with a cool engine and remove oil filter to gain access to left side mount top nut. Remove the center 17mm top nuts from both left and right mount brackets. The left side mount nut can be accessed from top, the right side I used a stubby 12point 17mm wrench and loosened from underneath.
Remove the radiator top mount brackets 10mm bolts and just lift the radiator slightly from base.
Depending on how your engine is of you are NA or Boosted check other things like catch cans, hoses and wires for enough slack that when engine is lifted few inches they wont break.
Now lift vehicle and undo power steering line bracket on left side of sub frame secured by a 10mm bolt. Loosen 2 17mm engine mount nuts on left and right side mounts. Unbolt Down pipe or whatever exhaust pipe you have.
Remove splash shields if you have any and unbolt the V brace. Be careful the No 2 control bushing might move down, so when the brace is removed snug the 17mm bolts for bushings back in so they don't pop out.
Put the support screw jack under oil pan with a block of wood and lift engine slowly. You can feel the movement in the mounts they are free at this time. But you need more clearance to get them out and swap new ones in.
Now position a Trans jack under the sub frame and Unbolt the steering rack and support it on jack. Mark the subframe with white out on left and right sides.
Loosen the 4 17mm nuts securing the sub frame to the body, it will move down slightly but because the sway bar control arms and struts are holding it still it wont come all the way down.
Have a friend pull down on Sub frame a little bit while you take one mount out at a time. Swap the metal hat and rubber cap on new mounts and Reinstall.
Install is reverse of removal. Make sure subframe is aligned to the marks you made earlier.
Take your time don't rush recheck everything for tightness and install a new oil filter and refill oil to proper level.